One form of integrated circuit package, called gull-wing because of the shape of the leads, is a popular surface mount design that is easy to solder and inspect. But since the leads are thin and extend away from the body of the package the leads are easily bent or broken. It is important to protect these leads especially for expensive large scale integration (LSI) chips. LSI is herein used as a generally descriptive term for any of the larger packages with large ICs, multiple hybrid ICs, or any other composite type construction. LSI is not limited to a narrow definition.
IC manufacturers routinely package these ICs in trays or carriers that protect the IC pack from static charge and physical harm during routine handling and shipping. It is important to protect the fragile leads. These trays or carriers often provide guides that substantially enclose the leads. Such guides prevent the test/burn-in or other use of the ICs while still packaged.
IC end users and test houses prefer, to reduce handling of the chip (herein defined as the packaged IC), to use the trays in which the chips are shipped. ICs often go through a series of handling operations that are a source of failure for such ICs; the ICs are: removed from the shipping carriers, placed in programming/test/burn-in fixtures, programmed/tested, repackaged for stocking or subsequent shipping, and then placed in another socket/fixture or soldered to a PCB for use. This handling (or mishandling) is a source of harm to the ICs.
Sockets are routinely used on PC boards to allow the IC to be changed or interconnections modified as the circuitry and programming are being debugged or upgraded. But in production, sockets are a source of failure, usually due to mechanical problems of alignment, unreliable electrical contacts and sometimes added capacitance and inductance associated with the socket itself. In addition there is an added cost of the socket. Sockets are often bulky with high profiles obviating their use in closely stacked board assemblies. These negatives are balanced by the ability of replacing or reprogramming the chip without damaging the PC board. This is important since LSI chips and completed PC boards are expensive, and replacing a soldered on chip without damaging the board or the replacement chip is a skill that is not routinely done nor recommended in production or even in development environments.
As shown in U.S. Pat. No. 5,266,037 the IC package is maintained within the carrier by a pair of spring clips. It is important that the IC package be held within the carrier in a fixed relationship thereto and prevent any damage to be inflicted to the IC package during transport or use.
It is clearly evident that the need for holding IC packages within the carrier is of great importance, especially with respect to gull-wing leaded integrated circuits.
It is therefore an object of this invention to provide an integrated circuit carrier system which effectively holds an integrated circuit (IC) package in position within the carrier during transportation and/or testing thereof.
It is a further object of this invention to provide an integrated circuit carrier system which incorporates therein four oppositely disposed locking clips in order to securely hold the IC package within the carrier even if one of such clips are inadvertently removed or damaged.
It is even a further object of this invention to provide an integrated carrier system which incorporates uniquely designed locking clips capable of locking into two different positions. A first position which securely holds the IC package within the carrier, and a second position which allows for accessible placement of the IC package into the carrier without additional external forces to hold the clip in this locked state.
It is still another object of this invention to provide uniquely designed locking clips which are light weight, extremely sturdy in construction and yet inexpensive to manufacture.